1. Field of the Invention
The present invention relates to a rolling mill in which rolling oil is supplied between work rolls for rolling a plate material in the thickness direction through the inside of the guide.
The present application claims priority of Japanese Patent Application No. 2005-348980 filed Dec. 2, 2005, the contents of which is incorporated herein.
2. Description of the Related Art
In a rolling mill in which a plate material is rolled by a pair of work rolls, for example, to form a sheet, rolling oil called coolant is supplied for cooling and lubricating the work rolls.
Some rolling mills are provided with multiple intermediate rolls in contact with the work rolls and the rotation of the intermediate rolls is transferred to the work rolls for rolling (see “Structure of 300 mm reverse rotation ten-step cold rolling mill (commonly called X mill) and rolling test results,” Shibakyo News (No. 43), pp. 6-22, 1966). In such rolling mills, sufficient space for supplying the coolant between the work rolls may not be assured because multiple intermediate rolls having a larger diameter than the work mills are provided in contact with the work rolls.
When sufficient space for supplying the rolling oil between the work rolls is not assured, a coolant passage is formed within the guide provided for guiding the leading end of the plate material between the work rolls, through which passage coolant is supplied between the work rolls (for example, see the page 15 of the above reference).
On the other hand, apart from the coolant supplied between the work rolls, temperature adjusted coolant is applied to the work rolls to control the crown rate of the work rolls in some rolling mills.
However, even a sufficient space for supplying the coolant for cooling and lubricating the work rolls is not assured in rolling mills in which a passage within the guide is used to supply coolant to the work rolls, making it difficult to provide a header for applying coolant to the work rolls for controlling the crown rate.
Alternatively, the temperature and flow rate of the coolant for cooling and lubricating the work rolls can be adjusted to control the crown rate. However, the temperature and flow rate of the coolant for cooling and lubricating the work rolls should be adjusted within significantly limited ranges. Therefore, the crown rate of the work rolls cannot be changed over a sufficient range.
The present invention is proposed in view of the above problems and the purpose of the present invention is to improve the controllability of the crown rate of the work rolls in a rolling mill in which coolant is supplied to the work rolls through a passage formed within the guide.